Guided mode resonance-driven giant Goos-Hanchen shift in monolayer MoS2 based dielectric grating structure

The combination of monolayer transition metal dichalcogenides (TMDCs) and the periodic nanostructures allows the great chance to bring great breakthroughs in their optical properties, such as, exciton-polaritons and pho-toluminescence. Here we show the improved light-matter interaction, as manifested in enhanced Goos-Ha.nchen (GH) shift, in monolayer MoS2 based symmetric and asymmetric dielectric grating structures. It is found that the GH shifts can be drastically enhanced when monolayer MoS2 is bridged onto the symmetric and asymmetric dielectric grating layer, whose enhancement can be attributed to the excitation of the guided mode resonance in the dielectric grating layer. In particular, in comparison with the case of the symmetric dielectric grating with monolayer MoS2, the asymmetric grating with monolayer MoS2 has achieved the GH shift as high as 9490 lambda, which is about three times larger than that in the former structure. In addition, the magnitude and the sign of the GH shift can be controlled by the asymmetric factor and other geometrical parameters in the dielectric grating layer. Our work uncovers an alternative approach to improve and engineer the GH shift of layered TMDC semiconductors via the help of the dielectric grating structures, which might greatly facilitate their utilizations in optoelectric and photonic fields.

Automated summary

This study demonstrates the improved light-matter interaction in monolayer MoS2-based grating structures, resulting in enhanced Goos-Ha.nchen shift. The guided mode resonance in the dielectric grating layer contributes to the significant enhancement of GH shift. The asymmetric grating with monolayer MoS2 achieves a GH shift three times larger than the symmetric grating. The magnitude and sign of GH shift can be controlled by the parameters of the dielectric grating layer. This work reveals an alternative approach to improve and engineer the GH shift of layered TMDC semiconductors.